首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Almost everybody wants to live as long as possible. And given the enormous strides made in medicine and the health sciences duri
Almost everybody wants to live as long as possible. And given the enormous strides made in medicine and the health sciences duri
admin
2010-06-30
82
问题
Almost everybody wants to live as long as possible. And given the enormous strides made in medicine and the health sciences during the past 150 years, people could be forgiven for hoping that someday human beings will live, if not quite forever, at least far longer than at present. Since the mid 19th century, average life expectancy at birth has nearly doubled: from 40 years to 75. Today many people live past 100, and the oldest individuals have reached either 115 or 120, depending on whom you believe.
So it comes as something of a surprise to be told by the experts that human beings have taken life about as far as it can go. That is the serious conclusion of a report in Science magazine last week by S. Jay Olshansky and Christine Cassel. Unless an unexpected breakthrough in basic science that would prevent the aging process, the era of rapid increases in human life span has come to an end, at least in developed countries. Even if science could cure heart disease and cancer, which account for nearly 50 percent of all deaths in the U. S. , it is unlikely that the average life expectancy at birth would increase much beyond 85.
What makes the report so compelling is that it is based on simple mathematics. In the past, the upper limits of life have been guessed from actuarial tables by estimating how death rates would change if, say, the incidence of heart disease were halved. "We reversed the question," says Olshan sky. Taking an" engineering approach" his team members asked themselves how many death rates would have to be reduced in order to increase average life expectancy to 120 years. What they discovered, after running the numbers through a computer, was that big hits in current death rates in the U. S. would give only small lifts to life expectancy. For example, if some miracle of medicine can guarantee no one died before reaching age 50 (thus eliminating 12 percent of all deaths), the increase in average life expectancy would be only 3.5 years.
There seems to be a kind of built-in biological limit programmed into the cells of the human body. In laboratory experiments, human cells divide only about 50 times before they begin to fall apart like old cars. This planned loss of use on nature’s part makes a certain amount of evolutionary sense. Survival of the fittest, after all, rewards only those who reproduce, not necessarily those who reach old age, Once reproduction is over, human bodies may as well be throwaway goods, biologically speaking.
What is important for human bodies to renew?
选项
A、Evolution.
B、Biological condition.
C、Reproduction.
D、Old age.
答案
C
解析
根据文章第的最后一段可知人体的细胞有一个固有的生物限制,试验表明当细胞像旧汽车的零件一样报废之前,细胞要分裂50次。自然生物中这种既定的使用损耗体现了进化的意义。适者生存就是有利于那些能再生的,而不一定是那些最老的。一旦再生停止了,从生物角度讲人体也是可以丢弃的物品了。A、B和D都不是对人体更新重要的因素。
转载请注明原文地址:https://kaotiyun.com/show/GFJd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
AnswerQuestions71to80byreferringtothefollowingfourarticlesconcerningmentalillness.Answereachquestionbychoosin
A=WashingtonD.C.B=NewYorkCityC=ChicagoD=LosAngeles1.WashingtonD.C.Washington,thecapitaloftheUnited
A=WashingtonD.C.B=NewYorkCityC=ChicagoD=LosAngeles1.WashingtonD.C.Washington,thecapitaloftheUnited
InthepasttwoyearsI’vephoned,e-mailedanddinedwiththreepotential"idealhusbands".(Thisisaccordingtotheauntsor
AccordingtotheFBI,howmanyrobberiesweresolvedbythepolicelastyearintermsofpercentage?
OfficialsinTampaFlorida,gotasurpriserecentlywhenalocalfirmbuildingthestate’sfirstethanol*-productionfactoryp
"Themoregadgetsthereare,the【C1】______thingsseemtoget."saidHonoreErvin,co-authorofTheEtiquetteGirls:ThingsYouN
EversinceGregorMendel’sfamousexperimentswithhybridsweetpeas,ithasbeenknownthattheremustbeunitaryelementswit
theaccountingdepartment
EversinceGregorMendel’sfamousexperimentswithhybridsweetpeas,ithasbeenknownthattheremustbeunitaryelementswith
随机试题
在高温水中工作的18-8不锈钢随含碳量的增高,应力腐蚀裂纹的敏感性将()。
带有循环物流的化工生产过程中的单程转化率的统计数据()总转化率的统计数据。
Hewaslastseeninpubliconthe______ofhisdaughter’swedding.
对消费者提出的修理、重作、更换、退货、补足商品数量、退还货款和服务费用或者赔偿损失的要求,故意拖延或者无理拒绝的处罚有()
某公司在财产清查中发现材料盘亏1800元,经查明,一般经营损失1000元,能理赔的洪水灾害损失500元,不能理赔的洪水灾害损失300元,则最终记入“管理费用”账户的金额是()元。[2010年真题]
甲公司是一家制造业企业,只生产和销售一种新型保温容器。产品直接消耗的材料分为主要材料和辅助材料。各月在产品结存数量较多,波动较大,公司在分配当月完工产品与月末在产品的成本时,对辅助材料采用约当产量法,对直接人工和制造费用采用定额比例法。2016年6月有关
某企业制造费用中的电力费用与机器工时密切相关,机器设备的正常生产能力为1000万小时,此时也为最大生产能力。当生产能力利用程度为70%时,电力费用总额为1200万元,每月的固定电力费用500万元。下列说法中正确的有()。
“五月流血周”
Stampcollectionhaslongbeenrecognizedashavinganeducationalvalue.Thereiseveryreasontoencourageyoungpeopletotak
NoEnglishmanbelievesinworkingfrombooklearning.Hesuspectseverythingnew,anddislikesit,unlesshecanbecompelledby
最新回复
(
0
)